Shaping charge excitations in chiral edge states with a time-dependent gate voltage

TL;DR

This paper investigates how time-dependent gate voltages can shape charge excitations in chiral edge states, analyzing the effects of voltage shape, frequency, and gate geometry on the injected current and single-particle excitations.

Contribution

It provides a self-consistent Floquet scattering theory analysis of charge shaping in chiral edge states, emphasizing frequency-dependent screening and noise suppression for single-particle excitations.

Findings

Frequency-dependent screening significantly influences charge shaping.

Proper voltage shaping can suppress excess noise.

The method enables creation of true single-particle excitations.

Abstract

We study a coherent conductor supporting a single edge channel in which alternating current pulses are created by local time-dependent gating and sent on a beam-splitter realized by a quantum point contact. The current response to the gate voltage in this setup is intrinsically linear. Based on a fully self-consistent treatment employing a Floquet scattering theory, we analyze the effect of different voltage shapes and frequencies, as well as the role of the gate geometry on the injected signal. In particular, we highlight the impact of frequency-dependent screening on the process of shaping the current signal. The feasibility of creating true single-particle excitations with this method is confirmed by investigating the suppression of excess noise, which is otherwise created by additional electron-hole pair excitations in the current signal.